用javascript放大图片局部

<html>

<head>

</head>

<body>

<BR>

原图：<BR>

<BR>

局部放大图：<BR>

<!--

zoomImg.src = srcImg.src;

srcImg.height = srcImg.height/2;

var zoomRate = 5;

zoomImg.height = srcImg.height*zoomRate;

zoomImg.parentNode.style.width = srcImg.width;

zoomImg.parentNode.style.height = srcImg.height;

function zoom(){

var elm = event.srcElement;

h = elm.offsetHeight/zoomRate/2;

w = elm.offsetWidth/zoomRate/2;

var x = event.x-elm.offsetLeft;

x=x<(elm.offsetWidth-w)?x<w?w:x:elm.offsetWidth-w;

zoomImg.style.marginLeft=(w-x)*zoomRate;

var y = event.y-elm.offsetTop;

y=y<(elm.offsetHeight-h)?y<h?h:y:elm.offsetHeight-h;

zoomImg.style.marginTop=(h-y)*zoomRate;

}

//-->

</SCRIPT>

</body>

</html>